The inquiry is separate from the Serious Fraud Office investigation launched in January 2002.
A Serious Fraud Office spokesperson confirmed that the DTI had launched the investigation.
He said: "We are aware that Wragge & Co is looking at some aspects of the company on behalf of the DTI." The spokesperson said its own investigation was continuing.
It is understood that Wragge is finalising details of the inquiry, although it has yet to decide which directors it was targeting.
The investigation comes as financial concerns emerged this week over a former sister firm of Bickerton, Driver Construction.
The DTI inquiry will focus on the possible disqualification of directors
Driver was originally bought with Bickerton in 2001 by businessman John Aviss. It was then sold to former Bickerton director Peter Neagle in January 2002. Neagle left Driver last Friday.
A report by credit checking agency NPD into Driver, of Tring in Hertfordshire, noted that 122 court judgments had been passed against the company in the last year for a total sum of £130,814.
The report says: "Serious attention should be given to the detrimental judgment information. In view of the foregoing, it is suggested that interested parties should not proceed with unsecured dealings without first referring to the parent company."
The last report and accounts for the firm were posted in Companies House last December. They record that turnover doubled to £13.6m for the year to 30 June 2002. They also state that pre-tax profit stood at £199,183, although it posted a retained loss for the period of £722,177. It issued a dividend of £850,000.
The report states that the firm's share capital was bought by a firm called Trerice on 6 August 2002.